In a successive vertical oligopoly, a set of "sellers" produce some input to be transformed into a final product by a set of "buyers". On this two-sided market, a firm's profit increases with the number of firms of the other type and decreases with the number of firms of its own type. We examine...

Two types of agents interact on a pre-existing free platform. Agents value positively the presence of agents of the other type but may value negatively the presence of agents of their own type. We ask whether a new platform can find fees and subsidies so as to divert agents from the existing...